Disk drive devices using various kinds of media, such as optical disks, magneto-optical disks, and flexible magnetic disks, have been known in the art. In particular, hard disk drives (HDDs) have been widely used as storage devices of computers, and have been one of indispensable storage devices for current computer systems. Moreover, HDDs have found widespread application to moving image recording/reproducing apparatuses, car navigation systems, and cellular phones in addition to the computers, due to their outstanding characteristics.
An HDD comprises a magnetic disk for storing data and a head slider for accessing the magnetic disk. The head slider comprises a head element portion for reading data from and/or writing data to the magnetic disk and a slider on which the head element portion is formed. The head element portion comprises a recording element for converting electric signals into a magnetic field according to data to be recorded to the magnetic disk, and a reproducing element for converting magnetic field from the magnetic disk into electric signals.
The HDD further comprises an actuator for moving the head slider to a desired position above the magnetic disk. The actuator is driven by a voice coil motor (VCM) and rotates on a rotational shaft to move the head slider along the radial direction over the spinning magnetic disk, which allows the head element portion to access a desired track formed on the magnetic disk to read or write data.
The actuator comprises a suspension having elasticity and the head slider is secured to the suspension with an adhesive. Pressure caused by the air viscosity between an air bearing surface (ABS) of the head slider facing the magnetic disk and a spinning magnetic disk balances the pressure toward the magnetic disk applied by the suspension, so that the head flies over the magnetic disk with a specific gap.
In manufacturing HDDs, a test called a slider Dynamic Electric Test (slider DET) is conducted. A typical slider DET sets a head gimbal assembly (HGA), which is an assembly of a head slider and a suspension, to a test apparatus and performs actual read/write operations from/to a spinning magnetic disk. Thereby, the test evaluates the head slider's flying characteristic and recording and reproducing characteristics.
The HGAs satisfying the specification in the slider DET proceed to the next manufacturing step and the HGAs determined to be failed are discarded. Accordingly, when a head slider does not satisfy the specification, the suspension with the head slider bonded is discarded together, which has been a loss in manufacturing HGAs.
To eliminate this loss of suspensions in manufacturing HGAs, slider DET apparatuses in which head sliders are attachable and detachable have been proposed (refer to Japanese Patent Publication No. 2004-531014 “Patent Document 1”, for example). The slider DET apparatus has a suspension for the slider DET and the suspension has a socket for a head slider to be attached to/detached from. The socket is bonded to the gimbal of the suspension. In this way, the slider DET apparatus for a head slider singly achieves a test on the head slider prior to being mounted on a suspension of a product to eliminate the suspension loss because of a defect head slider.
The socket disclosed in the Patent Document 1 comprises an opening for placing a head slider therein and a clamp bar for pressing the head slider against signal terminals in the opening to hold the head slider. To generate clamping force by the clamp bar, beam springs are formed at the front and the rear (the leading side and the trailing side) of the opening (head slider).
The socket is a micro electro mechanical system (MEMS); a metal layer for signal transmission is formed by plating a silicon substrate shaped by etching. Although the mechanism for attaching/detaching head sliders may be formed directly on the gimbal, the socket of the MEMS attached to the gimbal can extend the life of the suspension used in the slider DET and can improve the stabilities of the suspension and the slider DET.
To conduct the slider DET accurately, it is important that the slider be positioned properly on the suspension (in the socket) and receive a load (clamping force) in a proper direction. To this end, when securing the head slider to the socket, it is important to move the clamper straight in the front-rear direction and not to move it in the left-right direction (radial direction when it is above the magnetic disk)
When the clamper of the MEMS hits the magnetic disk because of vibration of the HGA in the slider DET, the clamper may receive a force in the lateral direction. In such an occasion, if the clamper considerably displaces in the lateral direction, the head slider may be released from the socket or the MEMS may be broken. The same thing may happen when the clamper receives a shock in the lateral direction in handling the MEMS or the HGA.